About Configuring Multiple Degradation Mechanisms (DMs) for a Single RBI Criticality Analysis

The baseline RBI workflow uses one driving Internal Corrosion and one driving External Corrosion DM per RBI Criticality Analysis. The driving DM that is used for an RBI Criticality Analysis has the highest corrosion rate.

Your organization, however, may choose to rename Internal Corrosion and External Corrosion DMs or to add multiple Internal Corrosion DMs for a single RBI Criticality Analysis.

Prior to using multiple Internal Corrosion DMs or a configured External Corrosion DM, you must complete the following steps:

Expected Recommendation Behavior

When you use configured External Corrosion and/or multiple Internal Corrosion DMs for a single RBI Criticality Analysis, the expected behavior for some of the fields differs from that of an analysis driven by a baseline DMs. The following baseline field behaviors are affected by the use of configured DMs:

Recommended Interval Value for Recommendations

For a Recommendation generated for an Internal Corrosion DM, the Recommended Interval value is mapped from the corresponding Internal Corrosion DME.
For a Recommendation generated for an External Corrosion DM, the Recommended Interval value is:
- Mapped from the corresponding External Corrosion DME when Appendix F is used to generate the Recommendation.
- Mapped from the most conservative Half-Life from all Internal Corrosion DMEs linked to the Analysis when Appendices H or I are used to generate the recommendation.
For a Recommendation generated for a Cracking DM, the Recommended Interval is mapped from the most conservative Half-Life from all Internal Corrosion DMEs linked to the Analysis.

Half-Life Input to Policies (Appendices G, H, and I) in Strategy Mapping

For a Recommendation generated for an Internal Corrosion DM, the Half-Life policy input value is mapped from the corresponding Internal Corrosion DME.
For a Recommendation generated for a Cracking or External DM, the Half-Life policy input value is mapped from the most conservative Half-Life from all Internal Corrosion DMEs linked to the Analysis.

Action Interval

When you select the Consider the Half-Life when Determining Inspection Task Interval field on the RBI Global Preferences workspace, the interval for the action associated with an Internal DM is set to the Half Life of the correspond Internal Corrosion DME unless the Recommendation Interval is less than the Half-Life value.